AVOELNINGEN FOR DEPARTMENT OFVA-TEKNIK ENVIRONMENTAL ENGINEERING

Lunds Tekniska Högskola Lund Institute of TechnologyLunds Universitet Universëty of Lund

LIBRARYINTERNATIONAL REFERENCE CENTREFOR COMMUNITY WATER SUPPLY ANDSANITATION (IRC)

PLUNGE R SEALS

PER JOHPNSSON

DEN HM3 , HOLLi~ND

AUG. 1986

232.2—2358

TelefoniTele~hone Telex046.107000 LUNIVER

6.335~G“~

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PostadresslPostal addressBox 118$221 00 Lund

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GatuadresslOffice addressJohn Erlcssons vAg 1

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1

CONTENTS

Introduction

Rev i e..j

Results

2

3

L~fl~RY,NT N~ATO~~L~FE~NCE

CEN1i~ERC~CC:~.~~i’TYV~/~I~0U:~PLYAND EAN~T~JIc~~ ~C)P.O. [T: ~ ‘1~0~AD Th~HagueTel. (070) E ~ ext. l41~.2~

Conclusions 10

List of references 12

RN:LO:

a

INTRODUCTION

The dept. of Environmental Engineering, Lund Institute of Technology

have carried out laboratory tests on handpumps since 1992.

These results and results from other lab. tests and field tests have

pointed out the below ground parts of the pump to be the most wear

sensitive and most difficult to repair. Because of this the project

entered a new phase in cooperation with The World Bank and SIDA. The

new pro3ect is named “Preparation of quidelines for selection of

plunger seals” and consists both of laboratory testing of seals and

compilation of results from other test institutes and field tests.

.This report is the result of a literature study at IRC, Den Haag,

Holland, and discussions with their personal. It was carried out

durIng August 1996.

The objective for making this study is to get a better view on what

has been done and what is going on concerning plunger seals.

The discussion was primarily held with Mr Hofkes and valueable help

has been contributed from Mr Dietvorst and Ms Westerhof at the IRO

library.

Robert Hahn and Henrik Aspegren at the department are indebted for

being of great help when writing this report.

3

S

REVIEW

Laboratory tests and field tests have been made in various places in

the world. Below a list follows on institutions and others who have

been working with the subject or where information could be found.

IRC

Receives and collects material from a lot of sources concerning

handpumps in general, and publishes it in handbooks and newsletters.

I DRC

Collects and publishes results from tests on PVC—handpumps with

plunger rings.

Batelle Memorial Institution.

Involved in the development of the US—AID hand operated pump in the

late sixties and early seventies. Made a lot of lab. tests with

different materials for both plunger seals and cylinders.

The World Bank/UNDP

Is running the interregional project for Laboratory and Field Tes-

ting and Technological Development of Rural Water Supply Handpumps.

In this project extensive field tests are carried out in 17 count-

ries, and laboratory tests of handpumps at CATR, England and Lund

Institute of Technology. The World Bank is also involved in the

development of the Tara and Afridev handpumps.

4

S

Georgia Institute of technology

Continued the work after Batelle Memorial Institute with field

studies and lab, testing of derivates from the US—AID handpump.

CATR

Created a model and a program for laboratory testing of the whole

handpump. They started with the tests in 1979 and have since then

tested a great number of handpumps.

Lund Institute of Technology

Lab, testing of the cylinder assembly and development of quidelines

for selection of plunger seals.

lJniversityof_Malaya~fialaysia

Lab. testing of the Waterloo handpump (PVC, shallow well).

Lh~~niversity of Malawi

Field tests and Lab. tests of a shallow well pump without seals or

with plunger rings.

Chulalongkorn University, Thailand

Involved in the development of a shallow well FVC—handpump in coope-

ration with the WHO. The pump is working with leather seals.

5

S

Indian Inst. of Technology Science

Under Mr Rama Prasad tests were made to describe the characteristic

of the plunger seal. The tests consisted of both laboratory and

field tests.

Blair Institute, Zimbabwe

Field test and Lab.tests of a shallow well pump without seals or

with plunger rings.

Asian Institute of Technology, Thailand

Lab and field tests on the Waterloo handpump (PVC plunger rings).

India Institute of Public Health

Made a study on shallow well handpumps for the WHO, the tests con-

sisted of laboratory tests.

Ch i na

A laboratory have been set up in Brijma and one in Changsha but they

have not published any results yet.

Others

Manufacturers of handpumps carry out tests but do not publish the

results. Another source is respectively countries’ ministeries which

make field tests but as the maunfacturers do not publish it for of-

ficial use.

6

RESULTS

Factors affecting the duration and performance of plunger seals are

basicly the three listed below

1. The plunger seal

2. The cylinder

3. The plunger

THE PLUNGER SEAL

The material in the plunger seal varies from different synthetic

materials to leather treated in different ways. Both groups of seals

have their advantages and disadvanteges. One big problem when tes-

ting leather seals is the variation in quality and size between

seals of the same brand. It is therefore not sufficient to make a

single laboratory test on a seal, since it does not give a signifi-

cant result for that specific seal.

The variation in quality most likely depends on:

+ rawmaterial

÷ tanning

what kind of animal is used.

gender of the animal.

age of the animal.

the animal’s environment.

alti tude

climate zone

indoor/outdoor living

what kind of tanning process is utilized.

vegetable (different kinds)

chrome

vegetable/chrome

time duration between slaughter and tanning.

+ impregnation the efficiency of the tanning process.

what impregnator is used.

S

7

÷ manufacturing uni form instruments.

skill of labourers and management

S

Two different shapes of the plunger seal can be distinguished namely

the cup seal and the lip seal. It is nearly impossible to manufact-

ure a leather seal in the shape of a lip seal. There have been

discussions whether it is right to make synthetic seals in the shape

of a cup seal

Figure.

Size

A) Cup Seal B) Lip Seal

All leathers when under water absorb some of it and expand while

synthetic material do not expand at all. The swelling of a leather

seal must be controlled since the performance of the pump depends

highly on it. If it swells to much then the force needed to get the

plunger to its lower position is so high that the plunger stops in

the upper position. If the swelling is not enough the efficiency of

the pump will be low.

Mr Rama Prasad have made some tests of the swelling with different

seals. It shows that the swelling does not stop until after about

six days for leather from the best part of the hide. This self

adjustment of a seal is an advantage, if the cylinder is not comp—

letly circular or shows other irrigularity in its form. The opposite

8

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occurs when seals of synthetic material is used. it has to fit per-

fectly in the cylinder from the beginning since the expansion is

close to zero.

I”1’I”

U.

a

&

- 2 4 a i 10 12

nl.mb., .4 °‘

Figure. Water absorption in leatherseals of different quality.

(Handpumps:problems and search for remedies, 1979)

Material

Below a list follows of different materials used in seals and where

they have been tested.

Leather:

un tanned

veg. tanned leather

chrome tanned leather

veg/chrome tanned leather

Synthetic:

pol ythene

neoprene

natural rubber

nitrile rubber

PVC—rings

Indian Institute of Gcience,

Georgia Institute of Technology,

Batelle Memorial Institute,

LIT, CATR.

As above.

Asian Institute of Technology.

Of the above mentioned, a good quality leather seal and nitrile

rubber show the best testresults.

— p1d.S$S1It,. ,.rkm

9

Qual i ty

The advantage of a synthetic seal is the uniform quality from a

specific brand. A lot of improvement can be made when manufacturing

leather seals. A good quality leather seal has shown to be as good

as the best synthetic material in laboratory tests.

Location

Leather is as stated before an water absorbing material and the

cycle wet/dry is weakening the material. Therefore it is not recom—

S mended to use leather seals in a shallow well suction pump or in

pumps which do not have the seals under water all of the time. In

the cases mentioned above it is better to use a synthetic seal.

What effect the pressure has in deep wells on soft material is not

clearly stated but the deformation of the seal assumes to give

exstensive wear or even a total breakdown, if the seal is to soft

and the height is to low the risk that the seal would turn outside

in is high.

THE_CYLINDER

The smoothness of the cylinder is one of the big secrets to longer

seal life. Batelle memorial Institute made a few tests and Georgia

Institute of Tech, noticed the phenomen in a field test in Nicara-

gua/Costa Rica. The results show that Iron and poorly made cylinders

have to high roughness and is of no use in a handpump. Extruded

brass cylinders and coated cylinders have a very low smoothness. The

form of the cylinder is another factor in the choise of seal materi-

al. A synthetic seal demands a perfectly circular cylinder while the

expanding leather seal does not require this.

10

CONCLUSIONS

Below is a list what most likely have happened to a seal during a

breakdown.

1. A cylinder with to low smoothness or irregular form has been

used.

B. The leather seal does not fit in the cylinder. It is either to

small or to big, no consideration hase been given to the swelling

or seals with various quality have been used.

3. Synthetic seal is used in an oval cylinder or cylinder with irre-

gular shape.

4. Leather seals is used where wet/dry conditions occur for instance

in suction pumps.

5. The leather seals is of low standard, rawmaterial, tanning, imp-

regnation is not done professionaly.

6. The material of the seal is to soft that it deforms under the

pressure loads.

7. The impacts on the seal have been underestimated.

There are a few things to consider when choosing a plunger seal.

A lot of tests have shown that seals of good quality are performing

very well. The things that give the quality of leather is listed on

page 6. Even if the leather or synthetic seals are more costly to

purchase its a good investment in the long run since the cost of a

seal is about 17, of its replacement cost.

The use of a cylinder with a high smoothness rate is also important.

Some coatings are not wear resistant and the friction gets higher

due to wear.

Measurment have to be made on the fitness of the seal in the cylin-

der. Notice a week is required for a leather seal to swell.

S

11.

The use of leather seals in suctionpumps where wet/dry cycles occurs

is nothing to recommend.

If the cylinder is oval or has other irregularties it is better to

use a leather seal.

12

LIST OF REFERENCES

IDRC

IDRC-Sle, Laboratory and Handpump Testing.

Yav G. S.

IDRC—204e, Village Handpump technology research and Evaluetion in

As i a.

Sharp D. , Graham M.

IRC

Handpump Cataloug, Revised draft edition

Handpumps for use in drinking water supplies in developing countries

Technical paper nr 10.

Mc3unkin E.

Handpump Testing and Evaluation

Bulletin nr 15.

Handpumps for use in drinking water supplies in developing countries

Technical paper nr 23

Hofkes E. , Kah—lin C.

Batelle Memorial Institution

The development of a water pump for underdeveloped countries.

Sep. 29 1976

Frink D. W. , Fannon P. D.

The Continued dev. and field evaluation of the AID Hand operated

water pump

Avg. 28, 1970

Frink D. W. , Frink R. D.

13

Interim report dev. of a hand—operated water pump for developing

countries.

Avg 1, 1974

Fannon R. D.

Field research and testing of a water handpump for use in developing

countries.

Jan. 31 1975

Fannon R. D. , Frink D. W.

University of Science and technology

.U.S.T type well pump

Blaho M. ,Dr

Georgia Institute of Technology

First progress report an the evaluation of hand operated water pump.

Potts D. W.

Final report on the utilization/evaulation of and hand—operated

water pump.

Potts D. W.

Field evaluation of steel fabricated handpumps for the USAID/Domini—

can republic.

WASH field report nr 139 , Feb 1985.

Potts et alia.

Laboratory testing of Handoperated water pumps

WASH field report no 131 , Sep 1984

Potts D. W.

Ministry of the Interior, Thailand

Improvement of Hanpump design in Thailand.

Equipment control division

14

All India Inst. of technology

Study of Handpump (Shalloe well—tube for Who Unicef assisted pro—

jects and other rural water supplies.

Part 1. Report an laboratory testing.

Prof. SUBBA. RAD, Gupta S.

WHO regional office New Dehli March 1976

The Bangalore Pump

S Indian Institute of Science Bangalor.

Handpumps: Problems and the search for remedies.

Pasad P.

The University of Malawi.

Shallow well improvement research project report.

Mechanical Eng. Chulalongkorn University , Thailand

The development of an PVC Handpump

Malila et alia.

The World Bank/ UNDP

Laboratory Tests of Hand—Operated Water Pumps for Use in Developing

Countries: Interim Report. 1982

Report no 1.

Laboratory Evaluation of Hand—Operated Water Pumps for Use in Deve-

loping Countries. 1983

Report no ~. ( World Bank Technical Paper no 6.

15

Laboratory Testing of Handpumps for Developing Countries Final

Technical Report. 1984

Report no 3. ( World Bank Technical Paper no 19.

Handpump Testing and Development: Progress Report on Field and

Laboratory Testing. 1984

Report no 4. C World Bank Technical Paper no 29.

Handpump Testing and Development: Procedings of a workshop in China.

1984

Report no 5. C World Bank Paper no. 48.

Sample Bidding Documents for the Procurement of Handpumps. 1986

Note no 1.

Handpump Laboratory Test Results: SSW, Monarch, Monolift, Moyno,

Pek, Tara and Volanta Pumps. 1986

Note no 2.

CATR, Enqland

Varius reports on different pumps who have been tested, also publi-

shed in the World Banks reports.

Lund Institute of Technology

Handpump Testing and Development:

Part 1. Project description. 1982

Hahn R.

Part 2. Interim report. 1982

Hahn R.

Part 3. New design. 1983

Hahn R.

16

Part 4. The first year — results of completed and ongoing tests

Hahn R.

Part 5. The second year — results of completed and ongoing tests

Hahn R. , Johansson P.

Rural Water Supply in Developing Countries. 1985

Hahn R.

Journals of Interest

1. IRC Newsletter

P.O Box 93190

2509 AD The Hague

The Netherlands

2. World Water

P.O Box 101

26/34 Old Street

London EC1P 1JH

United Kingdom

3. Water Lines

Technology Publications Ltd.

9 King Street

London WC2E 8HW

United Kingdom

4. Journal of the Indian Water works Association

78 Shivaji Park

Bombay 400 028

I nd i a

5. Water supply

Pergamon Press Ltd.

Meadington Hill Hall

Oxford OX3 OBW

United Kingdom

6. Handpump Development News

B&R Consultants

C Huygenslaan 43

3351 XA Papendrecht

The Netherlands

17